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An analysis of V861 Sco- I. Light curve synthesis.
Howarth, I. D.
Photometry of V 861 Sco, a binary at one time suspected of containing a collapsed secondary, is analyzed using light curve synthesis techniques. A consistent solution is obtained under the (justified) assumption that the primary fills its Roche lobe; the secondary is found to be of spectral type approximately B2 V. The absolute dimensions of the c…
A spectrophotometric study of some cool white dwarfs.
Greenstein, J. L.
Spectrophotometry from the Hale reflector and the IUE of four cool (approximately 7000 K) white dwarfs having large parallaxes is reported. Practically the entire flux is measured, together with the bolometric luminosity, temperature and radius. Stein 2051 is found to be a DC, with an astrometric binary companion of type dM4. The helium-dominated …
Astrophysical properties of a luminous Wolf-rayet type object in the core of the extragalactic HII region IC 132 from an analysis of its lambda lambda 1200-6000 A spectrum.
Benvenuti, P.; Dodorico, S.
We discuss the λλ1200-6000 Å spectrum of the ionizing source of the extragalactic H II region IC 132 in M33. The optical spectrum shows a broad λ4686 Å emission: the UV data from lUE show emission lines of N V, N IV, N III, C IV and He II. The WR features suggest an early WN classification with equivalent widths about a factor of 2 weaker than in …
Molecules in celestial objects. IV. IUE observation of CO lines towards Be stars with low reddening.
Tarafdar, S. P.
IUE spectra of two Be stars with small colour excess are presented to show the presence of a number of absorption lines due to A-X transition of 12CO and 13CO. The column densities of 12CO and 13CO towards these two stars and upper limits for these molecules towards three other Be stars and towards plane…
A study of the binary system 58 Persei.
Stickland, D. J.; Lloyd, C.; Pike, C. D. +3 more
The spectroscopic (and astrometric) binary 58 Persei has been observed at optical wavelengths and with IUE. The system is shown to consist of a mid B-type main-sequence star and a late G-type supergiant at a distance of 320 pc.
Visible and UV observations of the giant early-type members of the Large Magellanic Cloud.
Nandy, K.; Willis, A. J.; Wilson, R. +3 more
Visible and UV observations of a sample of LMC members with V greater than 14 mag are presented. The sample contains an O9V star and B0-B3 giants. Their flux distributions in the IUE range are found to be the same as those of Galactic giants. The effective temperatures and radii of the LMC members are determined by comparison with models.
Ultraviolet spectra of planetary nebulae. 6 NGC 7662.
Harrington, J. P.; Lutz, J. H.; Seaton, M. J. +1 more
The planetary nebula NGC 7662 considered in the present investigation has been a popular object for detailed modelling. Two models are considered. In Model I, which is similar to a model considered by Harrington et al. (1979), dust absorption is neglected. The model cannot provide results which are in agreement with two types of observational data…
Detailed observations of NGC 4151 with the IUE -II. Variability of the continuum from 1978 february to 1980 may, including X-ray and optical observations.
Tanzi, E. G.; Tarenghi, M.; Perola, G. C. +13 more
NGC 4151 has been extensively monitored with IUE from 1978 February to 1980 May. The rather erratic behaviour of the ultraviolet light curve seems to be mainly due to variations which occur at rates which, if extrapolated, would produce factor two changes in time-scales between five and 30 days, implying a radius of the order of 0.01 pc for the so…
P-Cyg profiles observed in the ultraviolet and visible spectra of Wolf-Rayet stars.
Willis, A. J.
A semi-qualitative analysis of the UV P-Cygni line profiles observed in the IUE spectra of seven WN and three WC Wolf-Rayet stars is presented. The velocity characteristics of these profiles are presented and combined with complementary measurements from visible spectra, allowing an inspection of P-Cygni profiles encompassing a wide range of ionic…
Very extended ionized gas in radio galaxies-I. A radio, optical and ultraviolet study of PKS 2158-380.
Boksenberg, A.; Penston, M. V.; Snijders, M. A. J. +7 more
IUE observations of PKS 2158-380 show gas in a high state of ionization extending out to a radius of 15 kpc, with a spectrum which is inconsistent with local photoionization by hot stars, and a UV point source at the nucleus which can be fitted by a power law with a spectral index of -1.4. If the gas is distributed within the galaxy in such a way …